1. Field of the Invention
The present invention relates to methods and systems for automatically identifying non-labeled, manufactured parts.
2. Background Art
Bar code readers are used extensively in many retail industries, such as hardware stores, at checkout stations to identify tagged items affixed with bar code tags. An item is identified by means of its bar code using a database stored in a host computer. Typically, a description of the item and its price are printed on a hardware store receipt and an ongoing price total is kept as additional items are scanned.
The use of bar code readers has generally been well received by the public, due in part, to the reliability and reduced time spent in the checkout line. However, a reliable system is needed to identify items for which it is undesirable or impractical to attach bar code labels, for example, manufactured bulk parts, such as individual fasteners such as nuts and bolts. Such parts or items are typically not identified and recorded by a bar code reader since such items are typically not labeled with bar codes. Identification of manufactured bulk items is still a task for the checkout operator, who must identify the item and then manually enter an item identification code. Operator identification methods are slow and inefficient because they typically involve a visual comparison of the item with pictures of the items. This time-consuming process can cause bottlenecks at the checkout stations, reducing throughput and making customers unhappy.
U.S. Pat. No. 6,424,745 discloses a method and system for optically recognizing an object from a reference library of known products based on a spectrum of local radius of curvature of the object. A surface portion of an object is illuminated with a pattern of light that permits the extraction of three dimensional coordinates for a set of points on the surface portion of the object. An image data set of the surface portion of the object is then captured with a capture device that is positioned at an angular offset with respect to a source of the light. That is, the combination of the light pattern and the imaging device together generate a two dimensional captured image, from which it is possible to extract the three dimensional coordinates for the set of points on the surface portion of the object. A set of local radii of curvatures are then determined for selected data points in the image data set. A spectrum representing a distribution of the curvatures is then computed for the set of local radii of curvatures. If the data set is for the generation of a library of spectra, it is processed with a dimension reduction analysis to determine a single set of basis functions representing all of the objects and a corresponding set of basis coefficients for each different type of object. If the data set is for an unknown object, then the dimension reduction analysis and the basis functions are applied to the data set to generate an unidentified set of basis coefficients. This latter set is then statically compared with the reference library of spectra to identify the product or at least designate the closest known products.
U.S. Pat. No. 6,457,644 discloses an item checkout device which combines a produce data collector with an optical bar code data collector. The item checkout device includes a housing, a bar code data collector within the housing, and a produce data collector within the housing. In a preferred embodiment, the item checkout device includes an optical bar code data collector including a first housing, a scale within the first housing, a weigh plate on the scale including a first window for allowing scanning light beams from optical bar code data collector to pass and a second window, and a produce data collector within the first housing including a second housing containing an aperture adjacent the second window, a light source for illuminating a produce item on the second window with substantially uniform light, a light separating element for splitting light collected from the produce item into a plurality of different light portions having different wavelengths, a detector for converting energy in the plurality of light portions into a plurality of electrical signals, and control circuitry which digitizes the plurality of electrical signals to produce a digital spectrum from the produce item which contains information to identify the produce item for the purpose of determining its unit price.
U.S. Pat. No. 5,867,265 discloses an optical identification system which includes a light source with a broad wavelength spectrum that is directed on an object to be identified. Suitable optical components, such as, one or more collimating lenses gather light that is reflected from the object and direct this light into a spectrometer. The spectrometer disperses the collimated light using a dispersing element, such as one or more gratings, prisms or a combination of both, onto an array of detectors. The array of detectors may be comprised of a linear diode array or a charge-coupled device (CCD) array which indicates the amount of light at each of a finely-spaced set of wavelengths covering a wide spectral range. The detectors are sensitive over a wavelength region, for example, in the case of silicon detectors from near-infrared plus the visible region, e.g., from 250 nm to 1100 nm. The set of signals from the detectors is read with an analog to digital converter, and transferred to a computer in the form of a spectrum. A set of known spectra determine the reference spectra and the unknown test spectrum is compared with the reference sets. A software program in the computer compares the test spectrum with reference spectra sets utilizing a statistical program. The program takes into account how much the known spectra vary from one another in addition to the average values. A display reads out a list of possible matches in rank order that have a probability of match greater than a predetermined threshold. An operator checks that the first listed item is correct and either accepts the first choice or indicates the correct choice. As an alternative, the system could automatically accept the first choice.
U.S. Pat. No. 6,075,594 discloses a system and method for optically identifying a product from a reference library of known products based on a reflected spectrum of the product. A broad wavelength light source illuminates the product and a spectrometer receives and forms a plurality of finely spaced wavelengths from the reflected spectrum. A detector optically processes the wavelengths to generate signals proportional to an amount of light received at each of the wavelengths. The signals are normalized and pre-processed to form data sets which relates each of the signals to each of the finely spaced wavelengths. This is performed for all of the different products and compiled. A set of basis functions is then generated for all of the different products and a corresponding set of basis coefficients is generated for each of the different products. This information, along with an electronic label for each product, is stored to form the reference library. When identifying an unknown product, the system generates a set of basis coefficients for the product to be identified. This latter set is statically compared against the reference library to identify the corresponding set of basis coefficients most closely matching the unknown set of basis coefficients.
U.S. Pat. No. 7,044,370 discloses a method and system for self-checkout of items from a retail or non-retail establishment. The system verifies security by comparing a measured physical characteristic of an item with the stored security characteristic for that item and determining if the measured physical characteristic is within an operator-modifiable tolerance range. The operator-modifiable tolerance range is different for different items in the store. Moreover, a stored security characteristic of an item can be updated automatically. In addition, the system includes a dynamic-weight scale that reports a measured weight before the scale settles.
U.S. Pat. No. 6,598,791 discloses a self-checkout system for a retail establishment that allows a customer to checkout multiple items having respective identification codes. The system includes a computer having memory with a buffer, an identification code reader coupled to the computer for determining the identification of the items by the identification codes, a security verification mechanism coupled to the computer for verifying that the items actually being checked out from the retail establishment are the same as those identified by the identification code reader. The computer is adapted to store identification information of multiple items obtained by the identification code reader in the buffer before verifying that the items actually being checked out from the retail establishment are the same as those identified by the identification code reader.
U.S. Pat. No. 5,608,530 discloses a laser for producing a beam of radiation which is then refined in cross-sectional dimension by use of plano-cylindrical lenses. The refined beam of radiation falls incident on a part to be measured. The unobstructed portion of the beam is then bifurcated by a pair of reflective surfaces which produce non-parallel radiating beams; each beam comprised of the unobstructed portion of radiation which has passed radially opposed halves of the part. The magnitude of radiation present in each non-parallel radiating beam is then measured.
U.S. Pat. No. 4,831,251 discloses an optical device for discriminating threaded workpiece by the handedness by their screw thread profiles. The device present a pair of light beams which pass generally tangent to the workpiece at angularly displaced positions. The light beams are inclined to follow the helix direction of a given handedness of a workpiece. Upon axial advancement of a workpiece through the device, a chopped output from the photodetectors indicates that the handedness of the threads matches the inclination of the light beams. The oppositely threaded workpiece, however, provides a generally constant DC output. With appropriate signal processing electronics, an automatic system for discriminating workpieces by thread handedness is provided.
U.S. Pat. No. 5,383,021 discloses a non-contact inspection system capable of evaluating spatial form parameters of a workpiece to provide inspection of parts in production. The system causes parts to be sequentially loaded onto an inclined track where they pass through a test section. The test section includes a length detection array for measuring the length of the workpiece, which includes a source generating a sheet of light oriented in the longitudinal direction of the workpiece. The profile of the parts are evaluated by one or more light sources also creating a sheet of light oriented transversed to the longitudinal axis of the parts. Single channel photodetectors are provided for each of the sources which provides an analog output of the extent to which each sheet of light is occluded by the part. These outputs are analyzed through appropriate signal processing hardware and software to generate length and profile data related to the workpiece geometry.
U.S. Pat. No. 5,568,263 discloses a non-contact inspection system capable of evaluating spatial form parameters of a workpiece to provide inspection of parts in production. The system causes parts to be sequentially loaded onto an incline track where they pass through a test section. The test section includes a length detection array for measuring the length of the workpiece, which includes a source generating a sheet of light oriented in the longitudinal direction of the workpiece. The profile of the parts are evaluated by one or more light sources also creating a sheet of light oriented transverse to the longitudinal axis of the parts. First and second pairs of single channel photodetectors are provided for each of the light sources which provides a pair of analog outputs of the extent to which each sheet of light is occluded by the part, as well as an ability to eliminate noise or scintillation caused by a point source of light, for example with a laser light source. These outputs are analyzed through appropriate signal processing hardware and software to generate length and profile data related to the workpiece geometry.
U.S. Patent Application Publication No. 2005/0174567 discloses a system to determine the presence of cracks in parts. The presence of cracks is determined through the use of an imaging device and illumination source. The part is moved along a track where it is sensed by a position sensor to initiate the inspection. The illumination source protects a sheet of light onto the part to be inspected. The line formed by the intersection of the sheet of light and the part is focused onto the imaging device. The imaging device creates a digital image which is analyzed to determine if cracks are present on the part.